Reproductive phenologies of phyllostomid bats in Costa Rica

Abstract

Reproductive phenologies of populations are strongly molded by environmental variation because natural selection favors individuals that time energetically demanding portions of their life cycle to correspond with periods of high resource availability. To evaluate how seasonal variation in abiotic characteristics and resources affects reproductive strategies, comparison among reproductive phenologies of species that use different resources and across geographic locations is crucial. To facilitate comparisons, it is essential to employ a rigorous and consistent classification scheme. Yet, few studies on the reproductive phenologies of bats, important seed dispersal and pollination agents in the tropics, have employed a clear or consistent classification scheme. We employed concise criteria to classify reproductive phenologies of frugivorous (Artibeus jamaicensis, A. watsoni, Carollia castanea, C. perspicillata, and C. sowelli) and nectarivorous (Glossophaga soricina) bat species, as well as 3 feeding ensembles of phyllostomids in northeastern Costa Rica. All 6 species exhibited bimodal phenologies (2 peaks). Each of the 3 ensembles exhibited different phenologies (i.e., frugivores: bimodal; nectarivores: polymodal [3 peaks]; and gleaning animalivores: unimodal [1 peak]). Bat species that consume plant material evinced pregnancy peaks in the late dry season and middle wet season, whereas gleaning animalivores exhibited a single peak in the middle to late dry season. Examination of geographic and temporal variation in phenologies revealed that strategies of frugivorous and nectarivorous species were geographically and temporally invariant, whereas strategies of gleaning animalivores differed among geographic locations.